Technical Field
Aspects of the present disclosure relate to an imaging forming apparatus such as an electrophotographic copier, a printer, and a facsimile machine.
Related Art
An image forming apparatus may form images on photoconductors of developing units, primarily transfer onto an intermediate transfer body, and transfers the images onto a transfer medium.
When such an image forming apparatus outputs an image having a smaller proportion (hereinafter, referred to as print coverage) of a print area relative to an area in which an image can be formed, the amount of toner used for development is smaller. Accordingly, toner in the developing units is unlikely to be replaced, and the period in which toner remains in the developing units may increase, thus degrading the toner. The degraded toner is stirred and stressed for a long period of time, and a charging capability or a charge-holding capability decreases, which may cause a reduction in image quality due to cleaning failure. In addition, when the degraded toner is continuously charged for a long period of time and remains under stress, such as friction and pressure of a developing blade and a developing roller, toner adhesion might occur.
Hence, image forming apparatuses have been proposed that perform a refreshing operation.